1. Field of the Invention
The invention described herein relates to extracting data from a federated database system, that is, from a meta-database management system which transparently integrates multiple autonomous database systems into a single virtual database, that is, a federated database. The constituent database systems remain autonomous, separate, and distinct. The method, system, and program product described herein are directed to searching for data stored in a federated, distributed computer system and to the management of the distributed database, including the database data and file access and retrieval, and retrieval of database data and files from a federated database. A further aspect of the invention includes organizing and inter-relating data or files, including relational, network, hierarchical, and entity-relationship models.
2. Background Art
A federated database system is a type of meta-database management system (DBMS) which transparently integrates separate, distinct, multiple autonomous database systems into a single federated database. The constituent databases are interconnected via computer networks, the internet, local area networks, and virtual networks and may be geographically decentralized. Since the constituent database systems remain autonomous, a federated database system is an alternative to the non-trivial task of merging together several disparate databases.
Through data abstraction, wrapper functions, and container functions, federated database systems can provide a uniform front-end user interface, enabling users to store and retrieve data in multiple databases with a single query, even if the constituent databases are heterogeneous. To this end, a federated database system must be able to deconstruct the query into subqueries for submission to the relevant constituent DBMS's after which the system must consolidate or aggregate the result sets of the subqueries.
Because various database management systems employ different query languages, federated database systems must frequently apply wrappers to the subqueries to translate them into the appropriate query languages.
Federated databases have heretofore been variously predicted to be capable of solving a myriad of problems at the conceptual level. However, for real world, practical problems, federated databases have not lived up to the predictions. One particularly vexing challenge is obtaining optimal solutions for multi-dimensional physical and “people” challenges.
Thus, a clear need exists to look at a problem beyond the database metadata level and the machine level, and to explore the solution space and associated soft constraints. By soft constraints we mean legal and institutional constraints, such as confidentiality and ethics, availability of people, performance requirements, and the like.